The present invention relates to solid-state capture and display devices, in particular, the integration of both light-emitting and light-capturing means in a common solid-state device.
Image display devices are well known and are based upon a variety of mechanisms such as electron-beam stimulated phosphors, liquid crystal displays, light-emitting diodes, vacuum fluorescence, and even arrays of light bulbs. Likewise, image capture devices are commonly used with a variety of technologies such as film or the solid state capture of photons using charge coupled devices (CCDs). These image capture devices all require an external source of scene illumination to create the photons they detect.
Typically, a system will rely on an illuminator (such as sunshine, camera flashes, or incandescent and fluorescent lights) to light a scene. The light from the scene is then focused through suitable optics onto an imaging device. The imaging device captures the photons and enables either a re-creation of the scene at a later time (as conventional film does) or immediate analysis or playback (as with television and most solid-state devices such as CCDs). In every case, separate mechanisms for illumination and detection are used. In some cases, illumination can be ambient light. In other cases, lighting means must be provided. These lighting and optical mechanisms can be costly (depending on the system needs), make miniaturization difficult, need careful manufacture and alignment to be robust, and require a variety of component types. Moreover, modification of the frequency and exposure times is difficult.
A number of solid-state solutions to emitting light at various frequencies exist. Likewise, solid-state image capture devices, in particular CCDs, are well known and widely used. Generally, the light emission and sensing functions are not integrated in a common device, although hard-copy electro-optic read/write devices defined on or supported by a common substrate are known (EP 0 827 323 A1, by Stevens et al., published Mar. 4, 1998). U.S. Pat. No. 5,929,845, issued Jul. 27, 1999 to Wei et al., references the use of a common technology for organic LEDs to serve as both light emitters and sensors alternately. Both systems meet some of the needs cited above, but do not address exposures with various light frequencies, the organization of sensors and emitters.
There is a need therefore for an improved image capture device and method that includes self- illumination, is simple to manufacture, and supports a variety of color exposure mechanisms.
The need is met according to the present invention by providing a self-illuminating solid-state color image capture device, that includes: an array of light emitting elements and light sensing elements formed on a common substrate; the light emitting elements including first color elements adapted to emit light of a first color and second color elements adapted to emit light of a second color, and the light sensing elements being responsive to all emitted colors; and electronics coupled to the light emitting and light sensing elements for sequentially causing the first and second color elements to emit light and sensing the light reflected from a scene being captured with the light sensing elements.